Power transmission



March 29, 1949. R. A. ERsKlNE 2,465,438

POWER TRANSMISSION med nec. 21, 1945 2 Shasta-sheet 1 INVENToR Easier E. kim/5 TT-EE- wf Hrramr March 29, 1949. R, A, ERSKME '2,465,438

I POWER TRANSMISSION Filed Dec. 21, 1945 2 Sheets-Sheet 2 Patented Mar. 29, 1949 POWER TRANSMISSION Robert A. Erskine, Detroit, Mich., assignor to Vickers Incorporated, Detroit, Mich., a corporation of Michigan Application December 21, 1945, Serial No. 636.340

4 claims. l

This invention relates to power transmissions, particularly to those of the type comprising two or more fluid pressure energy translating devices, one of which may function as a pump and another as a fluid motor.

This invention is more particularly concerned with providing means to be incorporated in a hydraulic transmission for automatically producing a continuous reciprocating movement of a reversible fluid motor. A simple way of producing this reciprocal movement is to incorporate in a panel a fluid pressure operated reversing valve for directing fluid to and from the motor and a pilot valve operated by the motor at each end of the motor stroke for controlling the reversing valve. One defect of the panels designed in the past was cumbersomeness caused by their weight and size. it is a problem to design a panel containing a minimum number of passages and ports connected to the pilot Valve and reversing valve. By reducing the number of passages and ports to an absolute minimum, the size of the panel may be greatly reduced in size and weight and, in addition, the manufacture of the same is simplified and the ultimate cost of the panel is reduced.

It is accordingly an object of the present invention to provide an improved unitary control panel containing the necessary control elements for producing a continuous reciprocating opera? tion of a reversible fluid motor which will be light in weight and small in size.

It is also an object of this invention to design the housing of the control panel and a pivot valve contained therein in such a manner that the -same bore used for mounting the pilot valve is also used as an external tank port, thereby eliminating a plurality of passages and reducing the size and weight of the panel.

It is also an object of this invention to provide an improved unitary control panel containing the necessary control. elements for automatically producing a reciprocatory operation of a reversible fluid motor which is readily adaptable for mounting against a block containing all circuit connections.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of the present invention is clearly shown.

In the drawings:

Figure 1 is a diagrammatic view of a hydraulic transmission incorporating a preferred form of the present invention.

2 Figure 2 is a side view of a. portion of the devic shown in Figure 1.

Figure 3 is a diagrammatic view of a hydraulic i transmission incorporating a preferred form of the present invention but with the parts in a different position than shown `in Figure 1.

Figure 4 is a center sectional view of the device shown in Figures 1 and 3 but with the parts shown in Figure 2 rotated midway between the positions shown in Figures 1 and 3.

Referring now to Figure 1, there is shown a pump Ill which may be driven by an electric motor I2. The pump I is connected to a tank It by means of a suction conduit I6 and is connected to a pressure port I8 of a unitary control panel by means of a pump delivery conduit 22. Panel 2li also has a tank port 2t (Figure 4) which is connected to tank It by means of a conduit 28 and motor ports 28 and 30 which are connected to opposite ends of a reciprocal motor 32 by means of conduits 3d and 36.

Incorporated in pump delivery conduit 22 is a suitable relief valve 38 which preferably is constructed in accordance with the patent to Vickers,

g5 No. 2,043,453. Valve 3B may be vented to unload pump I0 in order to stop motor 32, or said vent may be closed in order to start and operate motor 32. A manually-operated, two-way control valve it is connected to a venting port t2 of valve 38 by means of a conduit 4t and connected to tank It by means of a conduit it for this purpose.

Also incorporated in pump delivery conduit 22 is a flow-control valve i8 which preferably is constructed in accordance with the patent to Vickers. No. 2,272,684. The manner of operation and purpose of valve t8 is well-known in the prior art. Valve t8 will regulate the amount of fluid now ing to motor 32 from pump II! so as to regulate the speed of a piston 50 reciprocably mounted therein and to which is connected a piston rod 52. The excess volume of fluid delivered by pump spool 66 having a'central land 68 containing a` groove 1li, a land 12 at the extreme right end and a land 'I4 at the extreme left end. A chamber 'I6 in bore 88, located between the left end of spool 88 and a plug 'I8 threaded into the left end of bore 88, is connected to bore 58 by means of a passage 80. A chamber 82 in bore 88 between the right end of spool 88 and a plug 88 threaded into the right end of bore 88 is connectedby means of a passage 88 to the opposite side of bore 88 on the same plane as passage 80. A passage 88 which is connected to pressure port I8 by a branch passage 80 centrally intersects bore 88 and continues to a point of intersection with bore 58. Motor port 80 is connected to bore 88 by means of a passage 82, and motor port 28 is connected to bore 88 by means of a passage 88. A pair of vertical passages 88 and 88 are connected to bore 88 by means of branch passages |00 and |02, respectively. Both vertical passages 83 and 88 intersect a longitudinal passage |08 which intersects bore 88 on a different plane than passage 88 and passages 80 and 88.`

. As is more clearly shown in Figures 2 and 4, pilot valve 80 consists of a piston |08 having an extended portion |08 for the attachment of arms |I and ||2, shown in dotted lines in Figures 1 and 3. Piston |08 has a pair of flats I|8 and I|8 connected by a drilled passageway I8. Piston |08 also has a longitudinal bore |20 which extends to a point just short of contact with flats I I8 and `I I8. Duplicate tank ports |22 and |28 are in communication with bore by means of passages I 2 8 and |28, respectively. Piston |08 also has cylinder ports |80 and |82 in communication with bore |20. Piston |08 is rotatably mounted in bore 58 so that the flat II8 will be in continuous communication with pressure passage 88, tank ports |22 and I 28 will alternately be in communication with passages 80 and 88, and. because of a groove |88 in piston |08 in line with cylinder ports |80 and |82, cylinder ports |80 and |82 will continu-i ously be in communication with passage |08. A small drilled passageway |88 connects bore |20 with the extended portion |08 of piston |08 to provide a means of lubrication.

Pilot valve 80 is adapted to be operated by dogs, not shown, mechanically attached to motor 82 by contact of said dogs with either arm I|0 or ||2 at the end of each motor stroke, in the well-known manner. Due to the fact that tank port 28 is formed at one extremity of bore 88 and the pressure port I8 and motor ports 28 and 80 are also brought out to a single ilat surface, panel 20 may be flange-mounted against 'a block |88 containing all circuitv connections, as shown in Figure 4. Block |88 contains a pressure connection |80 and a tank connection |82 adapted to register with pressure port 8 and tank port 28, respectively;

with suitable sealing rings |88 being provided to prevent leakage between said connections. Motor connections are also provided in the block, one of which is shown in dotted lines and indicated by the numeral |88, which are adapted to register with panel motor ports 28 and 88. As shown in Figures 1 and 3, suitable holes |80 are provided in the body 88 for bolting panel 20 to block |88.

AReferring now to Figure 1, in operation with electric motor |2 operating pump I0 and with control valve 80 shifted to close the venting port 82 of valve 88. fluid under pressure from pump I8 will be delivered by means of conduit 22 to the pressure port I8 of panel 28. lAs shown in Figure l, pilot valve 80 has been rotated in a counterclockwise direction when piston 80 of motor 82 completed a leftward movement so as to shift reversing valve 82.

Fluid under pressure entering pressure port I8 enters pressure passage 88 by means of branch passage 80 and is delivered by means of reversing valve 82, fiat II8, passage |I8 and flat ||8 to passage 80, entering chamber I6 to act against 5 land 'I8 of reversing valve 82, shifting the same rightwardly. Fluid expelled from chamber 82 of reversing valve 82 may ow to tank I8 by means of passage 88, tank port |22, passage |28, bore |28, tank port 28 and conduit 28. With reversing valve 82 shifted completely to the right, pressure fluid from pump I0 in passageway 88 is prevented from entering conduit 88 4by means of land 88 and is directed to conduit 88 by means of bore 88. passage 88, and motor port 28 to the left end of motor 82 so as to shift piston 80 thereof rightwardly. Discharging fluid from the right end of motor 82 enters conduit 88, port 80, passage 82, bore 88, passages |02, 88 and |08, and is conducted to tank |8 by means of groove |88 of piston |08, cylinder ports 80 and I 82, bore 20, tank port 28 and conduit 28.

When piston 50 of motor 82 has almost completed its rightward stroke, arm |I0 of pilot valve 80 will be contacted to shift pilot valve 80 clockwise as is shown in Figure 3. Fluid under pressure from pump I0 is now delivered by means of conduit 22, pressure port I 8, branch passage 80 and pressure passage 88 to fiat I|8 where it is delivered to flat ||8 by means of drilled passageway ||8. When pilot valve 80 has rotated completely, the flat ||8 is no longer in communication with passage 80 but is now in communication with passage 88 solas to direct pressure uid from pump l0 to chamber 82 and cause reversing valve 82 to shift to the left. Discharging uid from chamber 18 at the left end of reversing valve 82 may flow to tank I8 by means of passage 88, tank port |28 of piston |08, passage I 28, bore |20, tank port 28 and conduit 28. Groove 'I0 in center land 88 of spool 88. prevents reversing valve 82 from hanging up during its cross-over at center position by permitting a continuous flow of fluid in passage 88 from port I8 to fiat ||8.

When spool 88 of reversing valve 82 has shifted completely to the left, land 88 will prevent pressure fluid in passage 88 being delivered by pump I0 from entering conduit 88 and direct the same to conduit 88 by means of passage 82 and motor port 80 from where it may enter the right end of motor 82 to shift piston 80 thereof to the left. Discharging fluid from the left end of motor 82 enters conduit 88, port 28 and passage 88. and is directed by land 88 and land 'I8 to passage |80 from where it is delivered by means of passages 88 and 08 to groove |88 of piston |08. Discharging fluid entering groove |88 is then directed by means of cylinder ports |80 and |82 to bore |28 where it iiows to tank i8 by means of tank port 28 and conduit 28.v When piston 80 has almost completed its leftward stroke, arm ||2 will be contacted so as to'again shift pilot valve 80 to the position shown in Figure l. 'Ihis will cause i'iuid to be again directed to chamber I8 and shift re versing valve 02 rlghtwardly so as to direct fluid to the left end of motor 82 shifting piston 88 in a rightward direction. This reciprocation of piston 80 will continue until it is desirable to stop motor 82 at which time control valve 88 may be shifted to vent valve 88 to tank I8 by means of conduits 88 and 88. and the full volume of pump I0 will be delivered to tank I8 by means of valve 88 and conduit 88.

Thus, pilot valve 88 is so constructed and is rotatably mounted in transverse bore 88 in auch a manner that, when rotated clockwise, comrnunication is 'established between the at H6 latter directing pressure iluid to the motor 32 and from the motor 32 to the pilot valve cylinder ports H30 and E32 which are in communication with tank bore l2!! of 'pilot valve t0.

Itvshould be noted that the speed of operation of spool 68 is unhindered by restrictions of any kind and is entirely dependent upon the total volume of fluid reaching chambers it or 82 and acting upon the eective area of lands 'l or 'li'.k

Due to this fact and also due to the fact that bore 58 is not only adaptable for mounting pilot valve S but, in addition, one extremity of the same is used as a tank port with which bore l20 of piston l06 is in direct communication, the diameters of spool 68 and of piston |06 may be much smaller` than ordinary valves of this type. Inaddition, the double application and employment of bore B for mounting pilot valve 60 and as a tank port eliminates the construction of supplementary passages usually necessary in panels of this type. Thus, with the size of reversing valve B2 and pilot valve 60 reduced to an absolute minimum, and the number of passages in the housing reduced to a minimum, the total size and weight of control panel 2t) is much less than previously-constructed panels of this type.

It should also be noted that, by constructing the pilot valve d@ with the tank bore B20 oonnected to the duplicate tank ports i122 and 26 and also to the cylinder ports i3@ and E32 and rotatably mounting the same in bore 58 so that tank bore i2@ is directly connected to external tank port 2li, panel 2t is adaptable to gasket mounting against a iat mounting surface bearing corresponding conduits therein registering with the external ports of panel 2d. While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow. l

What is claimed is as follows:

1. A unitary control panel for use in a hydraulic' transmission containing a fluid pump and reversible fluid motor adaptable for mounting against an adjoining block having corresponding circuit connectionssaid panel comprising a valve block, a -pilot valve spool rotatably mounted within a bore of said block, external pressure motor and tank ports, said tank port being formed as an integral part of and at one extremity of said bore, said pilot valve spool having a pair of pressure iiats, a passage connecting said ats, means torming a cavity in said spool, and duplicate tank ports and a plurality of motor ports in communication with said cavity, said spool being mounted in said bore so that said cavity is in direct alignment and communication with said external tank port, a iluid pressure operated reversing valve reciprocably mounted in said valve block controlled by said pilot valve, said reversing valve including motor ports connected to said pilot valve motor ports, a pressure passage connected to the external pressure port, to the reversing valve and to one of the pilot valve flats, and means for rotating the pilot valve at each end of a motor stroke whereby a pressure at is connected to one end of the reversing valve, a pilot valve tank port to the opposite end thereof and a reversing valve motor port through which fluid 'is adapted to ow from the motor to the pilot valve motor ports.

2. A unitary control panel for use in a hydraulic transmission containing a. iluid pump and reversible iiuid motor adaptable for mounting against an adjoining block having corresponding circuit connections, said .panel comprising a valve block, a pilot valve spool rotatably mounted within a bore of said block, external pressure motor and tank ports, said tank port being formed as an integral part of and at one extremity i ternal tank port, a fluid pressure operated reversing valve reciprocably mounted by said valve block controlled by said pilot valve, said reversing valve including motor ports connected to said pilot valve motor ports, a pressure passage connected to the external pressure port, to the reversing valve and to one of the pilot valve flats, means for rotating the pilot valve at each end of a motor stroke whereby a pressure ilat is connected to one end of the'reversing valve, a pilot valve tank port to the opposite end thereof and a reversing valve motor port through which fluid is adapted to flow from the motor to the pilot valve motor ports, and means for mounting said panel against an adjoining block containing corresponding circuit connections so that the external tank port is in direct alignment and communication with the adjoining tank port of said block.

3. In a hydraulic transmission the combination oi' a fluid pump, a reversible fluid motor and a unitary control panel for producing alternate reversing cycles of said motor. said panel comprising a valve block, a pilot valve rotatably mounted within a bore thereof, a iluid pressure operated reversing valve controlled by said pilot valve reciprocably mounted within said panel, said reversing valve including motor ports, external pressure tank and motor ports, said tank port beingformed as an integral part of and located at one extremity of said pilot lvalve mounting bore, said pilot valve comprising a spool, means forming a cavity within said spool, tank ports in communication with said cavity, motor ports also in communication with said cavity, a pair of pressure ats, and a passage connecting said ats, said spool being mounted within said bore so that said cavity is in alignment and communication with said external tank port, a passage connected to said external pressure port, to the reversing valve, to one of the pilot valve ilats and to a source of pressure in the system, and means for rotating said pilot valve at each end of a motor stroke whereby a pressure fiat is connected to one end of the reversing valve, a pilot valve tank port is connected to the opposite end thereof and the reversing valve motor port throughwhich uid is returning from the motor is connected to the pilot valve motor ports.

4. In a hydraulic transmission the combination of a fluid pump, a reversible uid motor and a unitary control panel for producing alternate reversing cycles of said motor, said panel comprising a valve block, a pilot valve rotatably 7 mounted within a bore thereof, a fluid pressure operated reversing valve controlled by said pilot valve reciprocably mounted within said panel, said reversing valve including motor ports. external pressure tank and motor ports, said tank .port being formed as an integral part of and located at one extremity of said pilot valve mounting bore, said pilot valve comprising a spool, means forming a cavity' within said spool, tank ports in communication with said cavity, motor ports also in communication with said cavity, a pair of pressure ilats, and a passage connecting said ilats, said spool beingmounted within said bore so that said cavity is in alignment and'communication with said external tank port. a Passage connected to said external pressure port, to the reversing valve, to one of the pilot valve ilats and to a source of pressure in the system, means for rotating said pilot `valve at each end of a motor stroke whereby a pressure at is connected to one end of the reversing valve, a pilot valve tank port is connected to the opposite end thereof and the reversing valve motor port through which iluid is returning from the motor is connected to the pilot valve motor ports. and means for mounting said panel against an adjoining block containing corresponding circuit connections in such a manner that the external tank port oi said panel is in alignment and oommunication with the corresponding connection oi said adjoining block.

ROBERT A. ERSKINE.

REFERENCES CITED The following references are of record in the ille of this patent: 

